The -w compiler option determines which compiler warnings, if any, are output. Each possible warning is associated with a warning level, starting from zero (0) and increasing with the potential problems that may occur. A significantly high level value will have the effect of suppressing all warning messages.

Note that the param, escape, pedantic and next arguments provide additional warnings not ordinarily output, even by default.

If the -w option is not specified, it's as if -w 0 was used. The -w option can be specified multiple times.